Disc brake calipers are widely used in vehicle braking systems. Calipers are categorized into at least two main types including fixed calipers and sliding calipers. A fixed caliper's housing is generally mounted to the vehicle's steering knuckle or bearing housing by a rigid connection. A sliding caliper's housing is generally mounted to the vehicle's steering knuckle or bearing housing on a guide pin system and through a mounting bracket. By allowing a caliper to slide, forces on each side of the rotor are balanced, even when a piston is only provided on one side of the rotor. With a fixed housing caliper, pistons are provided on opposed sides of the rotor and forces are balanced hydraulically. A fixed caliper may be preferable in many applications since the balancing of forces is achieved in a closed environment that is not subjected to friction causing contaminates.
One way of providing a fixed caliper design, is to use a "one-piece" housing with a plug in the piston bore(s) of one side of the caliper to allow access to machine the bores on the opposite side of the caliper during manufacturing. A drawback of the plug design is that a true one-piece caliper housing is not achieved since the plug itself is a separate piece that requires additional processing and sealing features. An alternative way of making a fixed caliper is to use a two piece design where the caliper housing is split along the longitudinal direction of the vehicle (substantially in the rotational plane of the rotor), so that the two halves can be machined before assembly. This alternative type of caliper also requires additional processing and sealing features.
Even though brake calipers have been in widespread use for many years, a true one piece housing fixed caliper that uses fewer parts and processing steps still remains elusive. Accordingly, a need continues to exist.